Automatic transmission for automobiles

ABSTRACT

An automatic transmission for automobiles is disclosed. In the automatic transmission, a housing ( 1 ) is filled with transmission fluid. A pump ( 2 ), having an input shaft ( 6 ), is positioned at one side within the housing ( 1 ), while a turbine ( 3 ), having an output shaft ( 7 ), is positioned at the other side within the housing ( 1 ) while being opposed to the pump ( 2 ). Pluralities of turbine blades ( 3   a ), regularly arranged around the turbine ( 3 ), are changeable in their inclination angles relative to the axis of the output shaft ( 7 ) so as to allow the rotating speed to be changeable. A hydraulic pressure control unit controls the inflow and out flow of the transmission fluid for the housing ( 1 ) while controlling the hydraulic pressure within the housing. An air control valve ( 5 ) controls the inflow and outflow of air relative to the housing ( 1 ) in response to the inflow and outflow of the transmission fluid relative to the housing ( 1 ). A transmission control unit (TCU) controls both the hydraulic pressure within the housing ( 1 ) and the inclination angle of the turbine blades ( 3   a ) in accordance with operation conditions of an engine and a desired running speed of an automobile.

TECHNICAL FIELD

The present invention relates, in general, to transmissions forautomobiles and, more particularly, to an automatic transmission,designed to transmit the rotating force of an internal combustion engineto axles using the operational theory of a hydraulic clutch, and toaccomplish a desired transference of force from the engine to the axleswhile automatically changing the speed by automatically controlling thehydraulic pressure within the clutch in addition to controlling theadjustable angle of turbine blades of the clutch in accordance with boththe engine speed and the running speed of an automobile.

BACKGROUND ART

As well known to those skilled in the art, conventional handtransmissions for automobiles are designed to force a driver toappropriately change the position of a shift lever between severalstages by hand while controlling a clutch pedal with a foot inaccordance with the operational conditions of an engine and the runningspeed of an automobile. However, such a shift lever control motion inaddition to the clutch pedal control motion is somewhat difficult tounskilled drivers since it is not easy for such drivers to determine theoperational conditions of the engine or the running speed of theautomobile. The shift lever control motion in addition to the clutchpedal control motion is also inconvenient to skilled drivers and isfatiguing to drivers while driving a car.

Therefore, drivers recently prefer automobiles with automatictransmissions to automobiles with manual transmissions.

In a conventional automatic transmission for automobiles, a hydraulicclutch or a torque converter is installed on the power transmitting pathbetween an engine and the transmission, and so the transmissionundesirably has a large size and a complex construction, increasing theproduction cost of an automobile. It is also very difficult to installsuch a conventional automatic transmission in an automobile. Anotherproblem, experienced in the conventional automatic transmission, residesin that it is necessary to provide a large area within the automobilefor the large-sized transmission.

DISCLOSURE OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the prior art, and an object of the presentinvention is to provide an automatic transmission for automobiles, whichhas a simple construction and a small size capable of reducing theproduction cost of an automobile, and which is also designed for easyinstallation of the transmission on a small area within the automobile.

In order to accomplish the above object, the present invention providesan automatic transmission for automobiles, comprising: a housing filledwith transmission fluid; a pump positioned at a first side within thehousing and integrated with one end of an input shaft connected to anengine crank shaft, the pump being rotated along with the input shaft; aturbine positioned at a second side within the housing while beingopposed to the pump, with both an output shaft integrally extending fromthe turbine to the outside of the housing and a plurality of turbineblades being regularly arranged around the turbine, the turbine bladesbeing changeable in their inclination angles relative to an axis of theoutput shaft so as to allow a rotating speed to be changeable when arotating force of the pump is transmitted to the turbine through thetransmission fluid; a hydraulic pressure control unit used forcontrolling inflow and outflow of the transmission fluid for the housingwhile controlling a hydraulic pressure within the housing; an aircontrol valve used for controlling inflow and outflow of air relative tothe housing in response to the inflow and outflow of the transmissionfluid relative to the housing; and a transmission control unit (TCU)used for controlling both the hydraulic pressure within the housing andthe inclination angle of the turbine blades in accordance withoperational conditions of an engine and a desired running speed of anautomobile.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a partially broken perspective view, showing the conventionalpower transmission theory of transference of rotating force of a pump toa turbine through transmission fluid;

FIG. 2 is a diagram, showing the construction of an automatictransmission in accordance with the preferred embodiment of the presentinvention; and

FIGS. 3a to 3 c are views, showing the operation of the transmission ofthis invention, with the turbine blades being changed in theirinclination angles relative to the axis of an output shaft during theoperation of the transmission.

BET MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows the conventional power transmission theory of transferenceof rotating force of a pump to a turbine through transmission fluid.FIG. 2 is a diagram, showing the construction of an automatictransmission for automobiles in accordance with the preferred embodimentof this invention. FIGS. 3a to 3 c show the operation of thetransmission of this invention, with the turbine blades being changed intheir inclination angles relative to the axis of the output shaft duringthe operation of the transmission.

As shown in FIG. 1, a pump 2 with an input shaft and a turbine 3 with anoutput shaft are oppositely positioned within a housing 1 filled withtransmission fluid. When the pump 2 is rotated, the turbine 3 is rotateddue to kinetic energy of the transmission fluid inside the housing 1.The automatic transmission of this invention uses the above-mentionedpower transmission theory using such transmission fluid.

As shown in FIG. 2, the transmission of this invention comprises ahousing 1 filled with transmission fluid. A pump 2 is positioned at oneside within the housing 1. The above pump 2 is integrated with one endof an input shaft 6 that is connected to an engine crank shaft (notshown), and so the pump 2 is rotated along with the input shaft 6. Aturbine 3 is positioned at the other side within the housing 1 whilebeing opposed to the pump 2. An output shaft 7 integrally extends fromthe turbine 3 to the outside of the housing 1, with a plurality ofblades 3 a being regularly arranged around the turbine 3. The aboveturbine blades 3 a are designed to be variable in their inclinationangles relative to the axis of the output shaft 7 so as to allow therotating speed to be changeable when the rotating force of the pump istransmitted to the turbine 3 through the transmission fluid. A hydraulicpressure control unit 4 is provided in the transmission of thisinvention for controlling the inflow and outflow of the transmissionfluid for the housing 1 while controlling the hydraulic pressure withinthe housing 1. An air control valve 5 controls the inflow and outflow ofair relative to the housing 1 in response to the inflow and outflow ofthe transmission fluid relative to the housing 1. The transmission alsohas a TCU (transmission control unit) 11, which controls both thehydraulic pressure within the housing 1 and the inclination angle of theturbine blades 3 a in accordance with the operational conditions of theengine and/or the running speed of an automobile.

In FIGS. 2, 3 a, 3 b and 3 c, the pump 2 and the turbine 3 each areshown having four blades 2 a, 3 a. However, it should be understood thatthe number of each of the pump blades 2 a and the turbine blades 3 a isnot limited to the number shown in the drawings.

As shown in the drawings, the pump blades 2 a are fixed to the inputshaft 6 while being inclined to the axis of the shaft 6 at an angle ofabout 45°. The turbine blades 3 a are designed to be inclined to theaxis of the output shaft 7.

In order to adjust the inclination angle of the turbine blades 3 arelative to the axis of the output shaft 7, a step motor 8 is installedwithin the hollow interior of the output shaft 7 so as to be rotatablealong with the output shaft 7. A drive bevel gear 9 is integrated withthe shaft 8 a of the step motor 8. Four driven bevel gears 9′ commonlyengage with the drive bevel gear 9 so as to transmit the rotating forceof the motor shaft 8 a to four driven bevel gear shafts 10 whilechanging the power transmitting direction at right angles. The abovefour driven bevel gears 9′ individually form the shaft of each drivenbevel gear 9′ and are respectively connected to the centers of theturbine blades 3 a.

The electric power for the step motor 8 is output from a voltageregulator 12 under the control of the TCU 11. In order to allow theelectric power from the voltage regulator 12 to be applied to the stepmotor 8, the electric wire 8 b of the step motor 8 passes through thehollow output shaft 7 prior to being connected to an annular terminal 13exposed to the external surface of the shaft 7. The above annularterminal 13 is normally brought into close contact with a brush 14biased toward the terminal 13 by a compression coil spring. Aninsulating material 15 is provided along both edges of the annularterminal 13, thus almost completely insulating the annular terminal 13from the output shaft 7.

Therefore, electric power from the voltage regulator is applied to thestep motor 8 through the brush 14, the annular terminal 13 and theelectric wire 8 b.

The hydraulic pressure control unit 4 comprises a hydraulic cylinder 4a, which controls the pressurized transmission fluid for the housing 1.The operation of the hydraulic cylinder 4 a is controlled by a solenoid40 valve 4 b. The above solenoid valve 4 b is operated by the voltageregulator 12, which is controlled by the TCU 11.

The piston within the hydraulic cylinder 4 a moves to the right in FIG.2 and pressurizes the transmission fluid for the housing 1 in proportionto the forward voltage applied from the voltage regulator 12 to thesolenoid valve 4 b. Therefore, the hydraulic pressure within the housing1 is increased in proportion to the forward voltage for the solenoidvalve 4 b.

In the automatic transmission of this invention, the transmission fluidwithin the housing 1 is completely drained when a shift lever 16 isplaced at a neutral position. That is, in the case of such a neutralposition of the shift lever, a backward voltage is applied from thevoltage regulator 12 to the solenoid valve 4 b, thus allowing the pistonto completely move to the left within the cylinder 4 a in FIG. 2.

The air control valve 5 is operated under the control of the TCU 11 in away such that the air control valve 5 is opened in the case of inflowand outflow of air relative to the housing 1, and is closed in the caseof pressurizing the transmission fluid within the housing 1.

The above automatic transmission is operated as follows.

When the shift lever 16 is shifted to the neutral position “N”, the TCU11 senses the neutral position of the lever 16 and opens the air controlvalve 5. In addition, the TCU 11 controls the solenoid valve 4 b andcompletely moves the piston to the left within the cylinder 4 a in FIG.2. In such a case, the transmission fluid within the housing 1 is almostcompletely drained from the housing 1, and so the rotating force of thepump 2 is not transmitted to the turbine 3. That is, the output shaft 7in the case of the neutral position of the shift lever 16 is not rotatedregardless of the rotating motion of the input shaft 6. Therefore, adesired neutral position of the transmission is accomplished.

When the shift lever 16 is shifted to the drive position “D”, the TCU 11senses the drive position of the 40 lever 16 and opens the air controlvalve 5. In addition, the TCU 11 controls the solenoid valve 4 b andforces the piston to move to the right by a distance within the cylinder4 a in FIG. 2, and so the housing 1 is almost completely filled with thetransmission fluid. Therefore, the rotating force of the pump 2 istransmitted to the turbine 3, thus rotating the output shaft 7. Adesired drive position of the transmission is thus accomplished. In theabove drive position of the transmission, the automobile moves forwardeven when the accelerator pedal is not operated by a driver if thedriver does not operate the brake pedal.

When the accelerator pedal is operated, an engine throttle valve isopened. In such a case, the automatic transmission of this inventionautomatically controls both the hydraulic pressure within the housing 1and the inclination angle of the turbine blades 3 a in accordance withthe opening ratio of the throttle valve, or both the engine load and thedesired running speed of the automobile. That is, the transmission ofthis invention automatically performs a speed changing operation.

In an experiment, it is noted that the kinetic energy of thetransmission fluid within the housing 1 is changed in proportion to thehydraulic pressure within the housing 1. Therefore, the hydraulicpressure within the housing 1 is increased in proportion to the engineload or the desired running speed of the automobile.

In order to increase the hydraulic pressure within the housing 1, theTCU 11 controls the voltage regulator 12 so as to allow an appropriatevoltage to be applied to the solenoid valve 4 b, thus finally moving thepiston to the right in FIG. 2 by a desired distance within the cylinder4 a.

When the turbine blades 3 a are positioned at an inclination angle of45° relative to the axis of the output shaft 7 as shown in FIG. 3a, therotating force of the pump 2 is most effectively transmitted to theturbine 3. On the other hand, when the turbine blades 3 a are positionedin parallel to the axis of the output shaft 7 as shown in FIG. 3b, therotating force transmitted to the turbine 3 is most reduced.

When the shift lever 16 is shifted to the reverse position “R”, the TCU11 senses the reverse position of the lever 16 and controls the turbineblades 3 a so as to place the turbine blades 3 a at inversely inclinedpositions relative to the axis of the output shaft 7 as shown in FIG.3c. Therefore, the output shaft 7 is rotated in an inverse direction,and so the automobile moves backward.

In order to control the inclination angle of the turbine blades 3 arelative to the axis of the output shaft 7, the TCU 11 controls thevoltage regulator 12, thus allowing the voltage regulator 12 to apply anappropriate forward or backward voltage to the step motor 8 of theturbine 3.

In a brief description, the TCU 11 of the automatic transmission of thisinvention automatically and appropriately controls both the hydraulicpressure within the housing 1 and the inclination angle of the turbineblades 3 a relative to the axis of the output shaft 7 in accordance withboth the engine load and the running speed of the automobile, thusfinally performing a desired automatic speed changing operation.

Industrial Applicability

As described above, the present invention provides an automatictransmission for automobiles. The automatic transmission of thisinvention has a simple construction and a small size capable of reducingthe production cost of automobiles. Another advantage of thetransmission of this invention resides in that it is easily installed ona small area within an automobile.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

What is claimed is:
 1. An automatic transmission for automobiles,comprising: a housing filled with transmission fluid; a pump positionedat a first side within said housing and integrated with one end of aninput shaft connected to an engine crank shaft, said pump being rotatedalong with the input shaft; a turbine positioned at a second side withinthe housing while being opposed to said pump, with both an output shaftintegrally extending from the turbine to the outside of said housing anda plurality of turbine blades being regularly arranged around theturbine, said turbine blades being changeable in their inclinationangles relative to an axis of the output shaft so as to allow a rotatingspeed to be changeable when a rotating force of said pump is transmittedto the turbine through the transmission fluid; a hydraulic pressurecontrol unit used for controlling inflow and outflow of the transmissionfluid for the housing while controlling a hydraulic pressure within thehousing; an air control valve used for controlling inflow and outflow ofair relative to the housing in response to the inflow and outflow of thetransmission fluid relative to the housing; and a transmission controlunit (TCU) used for controlling both the hydraulic pressure within thehousing and the inclination angle of the turbine blades in accordancewith operational conditions of an engine and a desired running speed ofan automobile.
 2. The automatic transmission according to claim 1,wherein said hydraulic pressure control unit comprises: a hydrauliccylinder used for controlling the inflow and outflow of the transmissionfluid for said housing, and for draining the transmission fluid from thehousing with a shift lever being shifted to a neutral position; and asolenoid valve used for controlling an operation of said hydrauliccylinder.
 3. The automatic transmission according to claim 1, whereinthe inclination angle of the turbine blades relative to the axis of theoutput shaft is controlled by a blade control means, said blade controlmeans comprises: a step motor installed within a hollow interior of saidoutput shaft; a drive bevel gear integrated with a shaft of the stepmotor; four driven bevel gears commonly engaging with the drive bevelgear so as to transmit a rotating force of the motor shaft to fourdriven bevel gear shafts while changing the power transmitting directionat right angles, said four driven bevel gears individually forming ashaft of each of the four driven bevel gears and being respectivelyconnected to centers of said turbine blades.
 4. An automatictransmission for a vehicle, comprising: a housing fillable withtransmission fluid; a pump positioned at a first side within the housingand integrated with one end of an input shaft connected to an enginecrank shaft, the pump being rotated along with the input shaft; aturbine positioned at a second side within the housing while beingopposed to the pump, with both an output shaft integrally extending fromthe turbine to the outside of the housing and a plurality of turbineblades being regularly arranged around the turbine; means for varyingthe rate of rotation of the output shaft including means for selectivelychanging the inclination angle of the turbine blades relative to an axisof the output shaft such that the rotating force of the pump transmittedto the turbine through the transmission fluid is varied; means forinfluencing the torque transferred from the pump to the turbine throughthe transmission fluid including a hydraulic pressure control unit usedfor controlling the inflow of the transmission fluid into the housingand the outflow of the transmission fluid from the housing to therebycontrol the hydraulic pressure within the housing; an air control valvefor controlling inflow of air into the housing and outflow of air fromthe housing; a transmission control unit; means for providing thetransmission control unit with an indication of a desired torque to betransmitted from the pump to the turbine, the transmission control unitcontrolling the air control valve, in response to a neutral torqueindication indicating that the desired torque to be transmitted from thepump to the turbine is to be substantially non-existent, to permit theinflow of air into the housing, whereby the outflow of the transmissionfluid from the housing is facilitated; and means for providing thetransmission control unit with an indication of a desired vehicle speed,the transmission control unit controlling the operation of the torqueinfluencing means in coordination with the operation of the means forvarying the rotation of the output shaft such that, at each time a givendesired vehicle speed is provided to the transmission control unit, thetorque influencing means is controlled by the transmission control unitto achieve the respective desired torque which has been indicated to thetransmission control unit at that time while the means for varying therotation of the output shaft is controlled by the transmission controlunit to achieve the desired vehicle speed.
 5. An automatic transmissionfor a vehicle according to claim 4, wherein the hydraulic pressurecontrol unit includes a hydraulic cylinder for controlling the inflow ofthe transmission fluid into the housing and the outflow of thetransmission fluid from the housing including controlling a drainingoutflow of the transmission fluid from the housing in response to aneutral torque indication indicating that the desired torque to betransmitted from the pump to the turbine is to be substantiallynon-existent.
 6. An automatic transmission for a vehicle according toclaim 5, wherein the hydraulic pressure control unit includes a solenoidvalve for controlling an operation of the hydraulic cylinder.
 7. Anautomatic transmission for a vehicle according to claim 4, wherein themeans for varying the rotation of the output shaft includes a step motorinstalled within a hollow interior of the,output shaft, a drive bevelgear integrated with a shaft of the drive motor, and a plurality ofdriven bevel gears commonly engaging with the drive bevel gear so as totransmit a rotating force of the step motor shaft to the driven bevelgears.
 8. An automatic transmission for a vehicle according to claim 4,wherein the hydraulic pressure control unit includes a hydrauliccylinder for controlling the inflow of the transmission fluid into thehousing and the outflow of the transmission fluid from the housingincluding controlling a draining outflow of the transmission fluid fromthe housing in response to a neutral torque indication indicating thatthe desired torque to be transmitted from the pump to the turbine is tobe substantially non-existent, the hydraulic pressure control unitincludes a solenoid valve for controlling an operation of the hydrauliccylinder, and the means for varying the rotation of the output shaftincludes a step motor installed within a hollow interior of the outputshaft, a drive bevel gear integrated with a shaft of the drive motor,and a plurality of driven bevel gears commonly engaging with the drivebevel gear so as to transmit a rotating force of the step motor shaft tothe driven bevel gears.